Chiropractic tables are known for use in treating patients suffering from a variety of orthopedic and neuropathic maladies. Such treatments include placing the patient's spine in vertical flexion (head to chest motion), extension (head to back motion), lateral flexion (left and right motion) and rotation (turning motion), as well as coupling vertical and lateral flexion to produce circumduction. Chiropractic tables are described in U.S. Pat. No. 4,523,581 of Ekholm, U.S. Pat. No. 4,649,905 of Barnes, U.S. Pat. No. 5,794,286 of Scott et al., U.S. Pat. No. 5,954,750 of Steffensmeier and U.S. Pat. No. 6,679,905 of Peetros, et al. Chiropractic tables commonly include one or more sections, some or all of which may include a drop mechanism for use in treating a particular portion of the patient's body. Generally, these drop mechanisms include an actuating mechanism that allows the table section to move abruptly and rapidly through a controlled distance when a force or pressure is applied to a body part that is supported on the table section by a chiropractor or other therapist. It is also known for a chiropractic table to include an automatic mechanism that performs cyclical flexion of the patient's spine within predetermined parameters, and such a device is described in U.S. Pat. No. 5,423,861 of Kelley.
Other treatment mechanisms of various types are known for providing therapeutic or rehabilitative manipulation of a body part. Thus, for example, U.S. Pat. No. 5,320,640 of Riddle et al. describes a device for providing continuous passive motion to the cervical spine for therapeutic or rehabilitative purposes. The Riddle device includes a stationary body support for supporting at least a portion of the patient's back, and a pivoting head support for supporting the patient's head. The head support is adapted to pivot upwardly and downwardly with respect to the stationary support to passively exercise the muscle groups surrounding the cervical spine. The Riddle device also includes a patient control device by which a patient may control the speed of pivotal movement of the head support with respect to the stationary support. However, during the operation of the Riddle device to provide continuous passive motion to the cervical spine, a patient may experience pain or sensitivity if his spine is being extended or flexed beyond an angle which is comfortable. The Riddle device does include a remote on/off switch by which the patient may stop the operation of the device, but it provides no other means or mechanism for eliminating a patient's discomfort, and no means or mechanism for eliminating a patient's discomfort while continuing to provide a therapeutic benefit.
It would be desirable, therefore, if a therapeutic device could be developed for providing continuous passive motion to a patient's spine. It would also be desirable if such a device could be provided in the form of a chiropractic or therapeutic treatment table which includes one or more drop mechanisms. It would also be desirable if such a device could be provided with means for controlling the extension and flexion of the portion of the table which moves to provide continuous passive motion to reduce such motion while still providing a therapeutic benefit.